The present invention relates to a new and useful method and industrial robotic device for applying coatings or other spray coated layers, in uniform thicknesses and at appropriate angles of pitch, in field applications, such as roofing applications or pavement applications.
In the roofing applications, flat roofs are often made of polyurethane foam layers, which may be covered by various coatings, such as elastomeric coatings, such as silicone. It is difficult to maintain a uniform thickness when applying a foam or elastomeric material, which by its nature rises when applied to achieve a thickness above a roof base.
Furthermore, the faster that a foam applicator passes over a surface, the less volume of foam is applied, resulting in less of a thickness of the applied foam. To achieve thicker foam layers, a spray applicator is slowed down in velocity as it passes over the roof bases, so that more foam material is discharged per square unit of space of roof base being passed over by the spray applicator.
Various attempts have been made to apply foam uniformly, such as from an applicator moving at a uniform speed along a carriage track. However, at the end of each pass of an applicator over a portion of a roof base, the discharged foam is applied twice, i.e. once at the end of the pass to the edge, and again as it starts over above the previously applied foam, until the carriage can adjust to an unsprayed area.
Among prior art devices included U.S. Pat. No. 5,381,597 of Petrove which describes a wheeled robotic device for installing shingles on roofs. While it does not concern spraying of urethane foam upon a flat roof, it does describe a movable, wheeled carriage for use upon a roof.
U.S. Pat. No. 5,248,341 of Berry concerns the use of curved walls to accommodate spray paint applicators for curved surfaces, such as aircraft.
U.S. Pat. No. 5,141,363 of Stephens describes a mobile train which rides on parallel tracks for spraying the inside of a tunnel.
U.S. Pat. No. 5,098,024 of MacIntyre discloses a spray and effector which uses pivoting members to move an armature which holds a spray apparatus.
U.S. Pat. No. 4,983,426 of Jordan discloses a method for the application of an aqueous coating upon a flat roof by applying a tiecoat to a mastic coat.
U.S. Pat. No. 4,838,492 of Berry discloses a spray gun reciprocating device, wherein parallel tracks are used wherein each track is square in cross section, but further wherein each track guides a plurality of rollers thereon.
U.S. Pat. No. 4,630,567 of Bambousek discloses a spray system for automobile bodies, including a paint booth, a paint robot apparatus movable therein, and a rail mechanism for supporting the apparatus thereat.
U.S. Pat. No. 4,567,230 of Meyer describes a chemical composition for the application of a foam upon a flat roof.
U.S. Pat. No. 4,167,151 of Muraoka discloses a spray applicator wherein a discharge nozzle is moved transversally upon a frame placed adjacent and parallel to the surface having the foam being applied thereto. However, the applicator of Muraoka ""151 does not solve the problem of excess foam being applied at the end of each transverse pass of the discharge nozzle.
U.S. Pat. No. 4,209,557 of Edwards describes a movable carriage for a nozzle applying adhesive to the back of a movably advancing sheet of carpeting. Similarly, Australian Patent no. 294,996 of Keith describes a movable carriage for a nozzle applying a polyurethane foam coating to a movably advancing sheet.
U.S. Pat. No. 4,016,323 of Volovsek also discloses the application of foam to a flat roof.
U.S. Pat. No. 3,786,965 and Canadian Patent no. 981,082, both of James et al, describe a self-contained trailer for environmentally containing a dispenser for uniformly dispensing urethane foam upon a terrestrial surface, wherein the problem of xe2x80x9cskewingxe2x80x9d occurs at the completion of each pass at the boundary edges of the surface to which are urethane foam is being applied. James ""965 employs self-enclosed gantry robots to move the fluid discharge nozzle over the terrestrial surface.
U.S. Pat. No. 3,667,687 of Rivking discloses a foam applicator device.
U.S. Pat. No. 4,474,135 of Bellafiore discloses an apparatus for spraying a coating upon a spherical object supported by a post, which apparatus includes a curved track for providing orbital movement of a spray applicator about the exterior spherical surface of the sphere to be coated. While they are curved in nature, the curved tracks thereof are provided for orbital movement about the sphere, not to change the speed, tilt and direction of a linearly moving nozzle.
Another attempt to solve the problem of xe2x80x9cdouble sprayingxe2x80x9d at a pass edge has been described in U.S. Pat. No. 4,333,973 of Bellafiore, which describes a similar spray applicator, such as that of Autofoam(copyright) Company. This spray applicator includes a wheeled, self-movable vehicle having a carriage portion with a horizontal linear track thereon. The spray applicator moves from one end of the track to the other, opposite end of the track at the end of one pass, of the applicator, above a portion of a roof base, and then the applicator reverses direction upon the track.
However, to avoid the xe2x80x9cdouble sprayingxe2x80x9d problem noted above, the Autofoam(copyright) device has an on-off switch which turns the applicator off at an appropriate time at the end of a pass while the applicator is reversing direction, and re-starts the applicator a short time later when the applicator has started to move in the opposite direction.
Moreover, there are severe problems with this approach, as the constant xe2x80x9con-offxe2x80x9d starting and re-starting of the applicator causes fatigue to the metal or other material parts of the applicator, and a detrimental effect to the end product. In addition, the Bellafiore ""973 and Autofoam(copyright) devices are bulky and complicated to use.
Therefore, the objects of the present invention are as follows:
It is therefore an object of the present invention to provide a spray applicator for foam roofing which applies a coating of elastomeric foam of uniform thickness.
It is also an object of the present invention to provide a single yet efficient spray applicator for foam roofing.
It is also an object of the present invention to provide a spray applicator than can be disassembled into a few major parts for easy transport and reassembly on a roof without resorting to the use of a crane.
It is yet another object of this invention to provide a method for covering a large area of a roof with foam roofing using a continuous spray.
It is also an object of the present invention to provide a spray applicator with a nutating nozzle mount to minimize variations in coating thickness.
It is a further object of the present invention to provide a hand-held remote control to enable the spray applicator vehicle to operate without an on-board operator.
It is an object of the present invention to provide a method for continuous adhesive spraying and application of elastomeric sheet roofing material of a large strip areas of a roof.
It is a further object of the present invention to provide accessories for the spray applicator vehicle to permit its use for applying elastomeric sheet roofing material from a roll.
Yet another objective of this invention is to provide a method and apparatus to provide fabric reinforced foam roofing.
It is also an object of the present invention to improve over the disadvantages of the prior art.
In keeping with these objects and others which may become apparent, and to solve the problems inherent in the Bellafiore ""973 and Autofoam(copyright) spraying devices, the present invention uses one or more track rails, such as a double linear track of round cross section, as shown in the drawings herein, wherein there is an arcuate uphill end portion of the track at each side, so that the spray applicator, which moves along the one or more linear tracks, will accelerate in speed and tilt the discharge nozzle outward as it rolls up the curved uphill portion, thereby reducing the amount of foam applied to the edge portion of the roof at the end of a pass of the applicator.
To obviate the complicated mechanisms of the Autofoam(copyright) device, the present invention uses simple mechanics to move the spray applicator. For example, a radially extending swinging arm is provided for the sideways movement of the applicator along the track. To eliminate arcuate movement of the pivoting arm, a telescoping mechanism is provided, so that the spray applicator moves linearly, instead of arcuately, as the swinging arm moves about a pivot fulcrum point.
To further insure uniform thickness, the present invention further comprises various speed controls, so that an appropriate thickness can be applied for each pass.
For example, a rheostat controls the speed of the movement of the spray applicator, and an LED readout tachometer has a display dial with appropriate readings for appropriate speeds for corresponding desired thicknesses. Since the rate of flow of foam-producing material emanating from the nozzle is fixed, the ground movement speed of the applicator determines the weight of the coating per unit area applied. This, in turn, determines the thickness.
When a slope is desired on a flat roof, such as toward a drainage line, the ground speed of the foam applicator can be reduced on each successive pass away and parallel to the drainage line. This will result in a stepwise slope approximating the desired contour.
It has been found that a nutating nozzle holder, which tilts the nozzle a small amount cyclically as it traverses the track, can be used to minimize the variations in foam thickness (in the form of rounded ridges) due to the hollow-cone pattern of the nozzle.
Accessories can be added to the spray applicator so that it can be adapted for spraying adhesive on a roof or for automatically laying an elastomeric sheet covering such as Sure-Seal(trademark) Fleece Back 100 EPDM made by Carlisle SynTec Incorporated of Carlisle, Pa. over a polyurethane foam substrate. Accessories can also be added for imbedding reinforced fabric within the polyurethane foal substrate.
While the invention has been described for use in applying roofing materials on roofs, it is also usable for spray applications at ground level such as for pavement painting or sealing applications.